Aircraft



March 13, 1934..

E. B. WiLFORD AIRCRAFT 2 Sheets-Sheet 1 Filed Aug. 30, 1950 zwemn n M mm1 M C m. M, m 5% m w March 13, 1934 E. B. WILFORD 1,950,424

AIRCRAFT Filed Aug. 30, 1950' ZSheets-Sheet' 2 INVENTOR. flawewrd "3. W!3 ATTORNEY.

?utehterl Merl 13, N34

3 metrics.

This invention relotes to aircraft and more perticulerly to rototsblesustaining elements for aircreit. 4

in l ctent No. lfii'Ldiil, granted Uctober 7, recs, fieseler sud meiser,there was disclosed or roteteble susteinihg gyroplene element whichseveral features of novelty and edvsluced utility over previous attemptsat the solutiou oi the problem. The application noted, disclosed e shettiourheled for free oscillation with sirioils or bearing plenes mountedon opposite ends of the shaft but with the axis of the shaft extendinglongitudinally of the respective cirioils out of registry with thecenter oi pressure thereof. The unit thus provided Wes arranged tooscillate under aerodynamic action to keep the resultant bit or eacheirioil of the pair-in bel once. It has been discovered that with theconstruction disclosed in the application, it was necessary to moireshaft and other supportelemehts quite and rigid in order to providesufilcient strength to absorb the lifting moments imposed on the shortfrom the respective oirioils without destruction, strain or breakage.Moreover, with an airfoil of ordinary construction mounted on the spuror shaft, the center of pressure of each airfoil could not be disposedfor enough away from the axis of oscill'stiori to provide suflcientleverage as to oversome, with 'sufiicieut rapidity under all conditions,the inertia. of the shaft, and or the blades ettoched to it so as to beable to eliminate ell rolirig moments in the system Without providing onairfoil of such appreciable span or chord es 7 l to be unwieldy andiheiiicient.

fit is among the objects of this invention to improve the constructiondisclosed in the Rieseler and hreiser potent ebove identified; toimprove generally the art of aircraft; to provide e. rotatablesustaining element to which power may be applied to secure vertical liftof an airplane but which is also eveileble as a rotatable sustainingelement of the gyroplehe type if disconnected from the power source; toprovide e rotatable susteining element for airplanes of great strengthbut of appreciably lighter construction thou previous practices; toprovide in rotatable sustainleg elements of the Rieseler and Kreisertype a plurality oi shafts so arranged that upward bendirig moments oneach shaft are absorbed or counterecte-d by downward bending momentsincident to centrifugal force; to provide brake means for gyroplenes endlike rotatable elements; to improve the eficiency of gyroplenes; toprovide stobilizing means for aircraft of the gyroplane type (53H.Zed-d9) other objects and edvonteges as will become more apparent as thedescription proceeds.

In carrying out the invention'in a preferred to though purelyillustrative form, o coir oi uirioils are provided, each. rigidlymounted upon a. shaft mounted in bearings so that the shedt is at a,slight angle to the horizontal, with'the shafts coupled for drivingrelation one with the other. This assembly provides for sheits of lightconstruction inasmuch es upward bending moments due to lift ereccunterected by the downward bending moments due to centrifugal forcesgeneroteol by rotetiou of the whole about u sub stentielly verticalords. do u iurther lecture of the invention, eech airfoil is ofsweep-beck" construction with its major area. being ofiset from the axisof oscillation in e curved tapered construction wherein the distancebetween the centor of pressureend the axis of rotation, aboveidentified, is appreciably increesed with on th crease in theaerodynamic cidclency oi eech sirfoil owing tothe disposition of thegreater ores thereof in e position where the peripheral speed of the,eirioil is greatest.

In. the uccompanying drawings:

Fig. 1 represents a. top lob of the improved susteinirig support of thisinvention,

2 represents e, front elevotioh'thereoi pectielly in section,

Fig. 3 represents a fragmentary verticol sectiohthrough the support ofthe unit,

Fig. 4 represents a diegremruetic illustration of the forces acting onthe shorts,

Fig. 5 represents a. iregmenterysectiou through it modified form ofuniversal connection oi the shafts,

Fig. 6 represents e, frsgmentery elem oi the modified form of universalconnection of the shafts disclosed in Fig. 5, and

Fig. 7 represents e plan oi on item of eircre'it of the gyroplone type,having it plurelity or roteteble sustaining elements with iridividuolbrelres on the respective elements to secure letere! stability of theaircraft.

In the preferred embodiment of the invention there are two peirs ofblsdes, each. blade of sirvfoil cross section, preferably, ore erreugedto traverse the same path oi rotation. In the disclosures of Figs. 1 end2 one pair of blades is shown as connected at the center throughgearing, while the intersecting transversely disposed pair of blades areshown as having as universal connec ion, but it will be understood ttonly till Mitt

desired pivotal relation may be used as, for instance, the concentricuniversal joints disclosed in Figs. 5 and 6 to be later described.

The fuselage 10 of any desired construction may carry a shortsupplemental transversely extending wing 11 upon which lateral controlsurfaces (not shown) may be mounted. Rising ver tically of the fuselageis a stationary turn-table 12 laterally braced as by struts 13 and,preferably, including a short cylindrical portion 14 upon which brakeshoes 15 are mounted. The brake shoes may be of any form and operated inany desired manner by. the pilot of the aircraft as will be clear. Theuse of brakes for stabilizing purposes will be described later. Avertical post 16 may be mounted axially of and through the turn-table12, the lower end of which may be firmly secured to the fuselage and theupper end of which may terminate in an annular flange 17. It ispreferred that the under side of flange 17 and the upper portion ofturntable 12 form race-ways for the reception of anti-friction or rollerelements, such as 18, arranged to rotatably mount the support for theblades to be described.- Obviously the bearing area will be proportionedto the load and to the stresses and strains incident to the use of theinvention, and the disclosurein Figs. 2 and 3 is not limitative butpurely illustrative.

The lower end of the rotatable support may comprise an annular plate 20having a depending annular flange 21 arranged to rotate in juxtapositionto the brake shoes 13 and the plate being apertured to receive the post16 and to be supported in vertical spaced relation between the flange 17and turn-table 12, as by means of the anti-friction bearings 18.Extending radially and upwardly from the outer edges of the plate 20 arethe arms 22 bridged horizontally by cross pieces 23. The cross pieces 23in addition to strengthening the unit form supports fora pair of meshedhorizontally disposed pinion gears 24, the upper portions of whichcomprise bevelled gears arranged to mesh with bevelled gears 25 carriedby the respective oppositely disposed shafts to be described. The arms22 and cross pieces 23 carry the. journals or bearings 26 and 27,respectively, the axes of each pair of which being slightly angularlydivergent from the horizontal so that shafts 28 and 30 mounted in -thebearings are also inclined to the horizontal. The respective bevelledgears 25 are rigidly mounted on the ends of the respective shafts sothat oscillation of one shaft in its bearings causes an equal andsynchronous and similar oscillation of the opposite shaft. In the otherpairs of journals 28, 27, the axes of which lie in a vertical planeperpendicular, preferably, to the axis of shafts 28 and 30, shafts 31and 32 are mounted with their axes also angularly divergent from thehorizontal and joined together by a universal connection -33.

Each shaft carries a blade of substantially airfoil cross sectionrigidly mounted upon the shafts as at 34, 35, 36 and 37. It is tobeobserved that the blades or airfoils are so disposed as to sweeprearwardly of the axis with the trailing edge and the side edge of eachairfoil merging or meeting in a point of intersection wellbehind theaxis of their respective shafts so that the axis of each blade passeslongitudinally through each blade for a limited distance when it emergesthrough the entering edge of the airfoil. By thus providing not onlythat the greater area of each airfoil is behind the axis of oscillationthereof,

but also that the major area is disposed in the path of rotation inwhich the peripheral speed is greatest, there is a combined eflfect ofan increase in the efficiency of the respective blades as well as thelocating of the center of pressure of each blade well behind the axis ofthe blade so that the lever arm from center of pressure to axis isincreased in length with an appreciable increase in the responsivenessof the blades to variations in lift to equalize their resultant lift. Inaddition to the stabilizing eilect attained by the dihedral of therespective pairs of blades particularly in lateral'displacement from aneven keel, or in lateral motion such as side-slipping, which is ofimportance, the invention attains appreciable savings in the weight ofthe structural elements used by so proportioning parts that the bendingmoments incident to the lift and which are generated between the outerbearings 26 and the tip of the blades, are substantially absorbed bydownward bending moments resulting as components of centrifiugal force.The relation of upward bending moment and downward bending moment issubstantially maintained no matter what the peripheral speed of thesustaining element may be, as each moment increases substantially inproportion to the speed of rotation of the unit. By

thus damping out the bending moments I am might otherwise be necessary.-

The geared connection disclosed in Figs. 1 and 2 ispurely illustrativepfone form of connection that may be used to insure synchronous action ofthe coupled blades while insuring that the respective pairs of bladesrotate in the same cone of rotation. As shown in Figs. 5 and 6, however,it is contemplated that the blades of one pair may have their shaftscoupled by a substantially universal connection permitting the slightdegree of oscillation necessary for the functioning of the device. Thus,shafts 31 and 32 are connected by their ordinary universal connection33, as will be understood, while the transversely disposed shafts 40 and41, will be provided with nesting semi-cylindrical yokes 42 and 43, thelegs of which have respectively slots 44' and pins 45 to establishdriving relation between the yokes, while permitting relative slidingmotion of the yokes to adjust themselves for oscillations of the,

It will be understood that the single rotor is a potential menace tobystanders at an airport, as it would normally continue to rotate at adangerous speed for an appreciable period after landing. The pilot mayapply the brake and retard or stop the rotor at any time he so desires,as when about to. land, or after contact has been made with the ground.The rotor of this invention is so strongly designed as to permit rapidacceleration or deceleration by the application of suitable means to thevertical axis thereof, in marked contrast to other types of rotors inwhich blades are transversely pivoted by hinges close to the verticalaxis and which may not be able to withstand the shearing strains imposedon the nee less Eeich rotor is provided with e. brsse, respectively 54end 55, each arranged in any desired manner, as to control device suchas s control stick or "is like in the fuselage (not shown) for eitherins veu'ldent or simultaneous sctustion by thepilot.

The sire being in flight, and e. situation arising requiring lateralstabilizing action, the pilot applies the brake on the high side, whichinstantly decelerstes that rotor, (53), thus slightly reducing itseiiective lift, with s resultsnt rill- 'Zerentiel lift sufidcient aswith the end of the ring carrying rotor 52 lowering to restore thelateral stability of the aircraft. Obviously the brake on the rotor soactuated will be released quickly to prevent the generation of onundesired rolling moment. When lending both brakes are ectustedsimultaneously if quicls stop of the rotors is desired.

It will be apparent that although in. the inter ests of simplicity therehas been disclosed but u pair of rotors, in lateral alignment, a greaternumber of rotors may be used and if they ere suitably distributed on theaircraft both longi tudinal end lateral stability may be accomplishedthrough suitable manipulation of the brakes on the respective rotors.

it is thought that the advantages occurring from the invention will beobvious.

l claim as my invention:

1. In aircraft, a, rotatable element including angularly divergentshafts mounted for free oscillation, oirfoils mounted on the respectiveshefts with the center of pressure of each airfoil lying behind the axisof its respective shaft, and means for supporting the shafts ande-irioils for bodily rotation about an axis, the shafts describing aflattened cone sothst upward bending moments exerted by the sirfoils aresubstantially counteracted by downward bending moment components ofcentrifugal force generated by rotstion of the sustaining element as awhole.

2. In. airplanes, a. rotatable sustaining unit including a pair ofoppositely disposed sirfoils, a. spur supporting each airfoil with thecenter of pressure of the airfoil lying behind the axis of oscillationof said shaft, and each airfoil comprising e. curved wing surface, thetip end of which is clear of the axis of said shaft.

merit comprised of means rotateble s. Err aircraft, o. roteteblesustohung element, comprised of two pairs of blades, as shaft supportingeach blade and each iournslled for support in 2. plane sngulerlydivergent from the horizontal, means connecting opposite elicits oi aspair through a pivotal connection such that all oi the shafts lie in thesome cone oi rotation.

4.. in aircraft, is rotatable sustaining element including angulerlydivergent shafts mounted infiexibly for free oscillation, ell-toilsmounted on the respective shafts with the center or pressure or eachairfoil lying behind the axis or its respective shaft, and means forsupporting the shafts and sirfoils for bodily rotation about on axis,the shafts describing it flattened cone so that upward bending momentsexerted by the airfoils are substantially counteracted by downwe-rdbendlng-momentcomponents of centrifugal force generated by rotation ofthe sustaining element as as whole, with e dihedral angle betweenopposing blades providing stabilizing eiroots;

5. in gyropienes, s rotctsble sustaining unit including 2. pair ofoppositely disposed oirioils, a shaft supporting each airfoil with thecenter of pressure of the airfoil lying behind the axis of oscillationof said shaft, and o, swept-beck plan form of the airfoil such that thedistance from the center of pressure oi on airfoil to the axis ofoscillation of its shaft increases from the root toward the tip of theblade, to provide a. lever arm of such length as to overcome the inertisof the oscillating system.

6. In gyroplsnes, a rotatable sustaining element comprised of a, pairoibludes, e, shaft supporting each blade and each journelled for supportin a plane angulerly divergent from the horizontal, means connecting theshorts through at driv= ing connection such that both shafts lie in thesome cone of rotation and so that the blades oscillate together.

'7. In gyroplanes, a, rotatable sustaining e1eabout a. substentisllyvertical axis, a. pair of blades, as shaft supporting each blade andeach iournolled for oscillation in the first mentioned means with theaxes of the shafts non-coincidental and ungulerly divergent, meansconnecting the shafts through a driving connection such that the bladesoscillate together in the some direction.

8. In gyroplanes, a rotating wing system com prising means defining anaxis oi rotstion of the system, a shaft journolled on said means andhaving an axis intersecting and lying in a. plane extendingsubstantially radially of said rotative axis, a blade mounted on saidshaft end so disposed that a line drawn from the center of one end ofthe blade to the center of the other end of the blade is rearwerdlyacutely sngulsrly divergent from the axis oi. sold short.

EDWARD. BURE Ki led

